bsl::optional

Synopsis

Declared in <bslstl_optional.h>

template<class t_TYPE>
class optional
    : public BloombergLP::bslstl::Optional_Base<t_TYPE>

Base Classes

Name	Description
`BloombergLP::bslstl::Optional_Base<t_TYPE>`	Component-private class template implementing `bsl::optional`.

Type Aliases

Name	Description
`allocator_type`	This `typedef` is an alias to `bsl::allocator<char>`.
`value_type`	Alias for the managed object type of this optional.

Member Functions

Name	Description
`optional` [constructor]	Constructors
`operator=`	Assignment operators
`and_then`	`and_then` overloads
`emplace`	Destroy any contained value and construct a new one in place.
`get_allocator`	Return allocator used for construction of `value_type`.
`has_value`	Return `false` if this object is disengaged, and `true` otherwise.
`operator*`	Dereference operators
`operator->`	Member access operators
`or_else`	Return this optional if engaged; otherwise invoke `func`.
`reset`	Reset this object to the default constructed state (i.e., to a disengaged state).
`swap`	Exchange the values of two optionals.
`transform`	`transform` overloads
`value`	`value` overloads
`value_or`	Return the contained value, or a converted fallback if disengaged.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, IsBitwiseCopyable, BloombergLP::bslmf::IsBitwiseCopyable<t_TYPE>::value>`	Nested trait declaration for `bslmf::IsBitwiseCopyable`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, IsBitwiseMoveable, BloombergLP::bslmf::IsBitwiseMoveable<t_TYPE>::value>`	Nested trait declaration for `bslmf::IsBitwiseMoveable`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, UsesAllocatorArgT>`	Nested trait declaration for `bslmf::UsesAllocatorArgT`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<Optional_Base, UsesBslmaAllocator>`	Nested trait declaration for `bslma::UsesBslmaAllocator`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<optional, IsBitwiseCopyable, BloombergLP::bslmf::IsBitwiseCopyable<t_TYPE>::value>`	Nested trait declaration for `bslmf::IsBitwiseCopyable`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<optional, IsBitwiseMoveable, BloombergLP::bslmf::IsBitwiseMoveable<t_TYPE>::value>`	Nested trait declaration for `bslmf::IsBitwiseMoveable`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<optional, UsesAllocatorArgT, BloombergLP::bslma::UsesBslmaAllocator<t_TYPE>::value>`	Nested trait declaration for `bslmf::UsesAllocatorArgT`.
`operator BloombergLP::bslmf::NestedTraitDeclaration<optional, UsesBslmaAllocator, BloombergLP::bslma::UsesBslmaAllocator<t_TYPE>::value>`	Nested trait declaration for `bslma::UsesBslmaAllocator`.
`operator bool`	Return `false` if this object is disengaged, and `true` otherwise.

Protected Type Aliases

Name	Description
`AllocType`	This `typedef` is an alias to `allocator_type`.

Protected Member Functions

Name	Description
`assignOrEmplace`	Assign or emplace a value into this optional.
`dereferenceRaw`	Return a reference to the contained value without checking engagement.

Deduction Guides

Name	Description
`optional<t_TYPE>`	Deduce the specified type `t_TYPE` from the corresponding type supplied to the constructor of `optional`.
`optional<t_TYPE>`	Deduce `t_TYPE` for an allocator-aware optional from a value.
`optional<t_TYPE>`	Deduce `t_TYPE` for an allocator-aware optional from another optional.

Friends

Name	Description
`bsl::optional`	Allocator-aware nullable wrapper for an object of type `t_TYPE`.

Non-Member Functions

Name	Description
`PrintTo`	Write the specified `value` to the specified `*stream`, surrounded by double quotes.
`make_optional`	Return an `optional` containing a value constructed from the arguments.
`make_optional`	Return an `optional` object containing a value-initialized `t_TYPE` object.
`make_optional`	Return an `optional` containing a value constructed from the arguments.
`make_optional`	Return an `optional` containing a value constructed from the arguments.
`make_optional`	Return an `optional` containing a value constructed from the arguments.
`make_optional`	Return an `optional` containing a value constructed from the arguments.
`make_optional`	Return an `optional` containing a value constructed from the arguments.
`operator!=`	Return whether the operands do not have the same value.
`operator!=`	Return whether the operands do not have the same value.
`operator!=`	Return whether the operands do not have the same value.
`operator<`	Return whether the left-hand operand is ordered before the right.
`operator<`	Return whether the left-hand operand is ordered before the right.
`operator<`	Return whether the left-hand operand is ordered before the right.
`operator<=`	Return whether the left-hand operand is before or equal to the right.
`operator<=`	Return whether the left-hand operand is before or equal to the right.
`operator<=`	Return whether the left-hand operand is before or equal to the right.
`operator<=>`	Perform a three-way comparison of the operands.
`operator<=>`	Perform a three-way comparison of the operands.
`operator<=>`	Perform a three-way comparison of the operands.
`operator<=>`	Perform a three-way comparison of the operands.
`operator==`	Return whether the operands have the same value.
`operator==`	Return whether the operands have the same value.
`operator==`	Compare a `std::optional` with a `bsl::optional` for equality.
`operator==`	Return whether the operands have the same value.
`operator>`	Return whether the left-hand operand is ordered after the right.
`operator>`	Return whether the left-hand operand is ordered after the right.
`operator>`	Return whether the left-hand operand is ordered after the right.
`operator>=`	Return whether the left-hand operand is after or equal to the right.
`operator>=`	Return whether the left-hand operand is after or equal to the right.
`operator>=`	Return whether the left-hand operand is after or equal to the right.
`swap`	Exchange the values of two optionals.
`swap`	Exchange the values of two optionals.
`swap`	Exchange the values of two optionals.
`::BloombergLP::bdlb::nullableValue_acceptsBslOptional`	Component-private constraint helper for `bsl::optional` conversion.
`::BloombergLP::bdlb::operator!=`	Return `true` if the specified nullable objects do not have the same value.
`::BloombergLP::bdlb::operator!=`	Return `true` if the specified nullable objects do not have the same value.
`::BloombergLP::bdlb::operator<`	Return `true` if `lhs` is ordered before `rhs`, and `false` otherwise.
`::BloombergLP::bdlb::operator<`	Return whether the left-hand operand is ordered before the right.
`::BloombergLP::bdlb::operator<=`	Return whether the left-hand operand is before or equal to the right.
`::BloombergLP::bdlb::operator<=`	Return `true` if `lhs` is ordered before `rhs` or they are equal.
`::BloombergLP::bdlb::operator==`	Return `true` if the specified nullable objects have the same value.
`::BloombergLP::bdlb::operator==`	Return `true` if the specified nullable objects have the same value, and `false` otherwise.
`::BloombergLP::bdlb::operator>`	Return `true` if `lhs` is ordered after `rhs`, and `false` otherwise.
`::BloombergLP::bdlb::operator>`	Return whether the left-hand operand is ordered after the right.
`::BloombergLP::bdlb::operator>=`	Return whether the left-hand operand is after or equal to the right.
`::BloombergLP::bdlb::operator>=`	Return `true` if `lhs` is ordered after `rhs` or they are equal.
`::BloombergLP::bslstl::optional_acceptsBslOptional`	Component-private constraint helper for `Optional_DerivedFromBslOptional`.

Derived Classes

Name	Description
`NullableValue`	Value-semantic wrapper that adds a null state to `TYPE`.